FRACTAL CHARACTER OF FRACTURE SURFACES OF METALS
FRACTAL CHARACTER OF FRACTURE SURFACES OF METALS
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DOI：
10.1038/308721a0
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发表时间：
1984-01-01
期刊：
影响因子：
64.8
通讯作者：
PAULLAY, AJ
中科院分区：
文献类型：
--
作者：
MANDELBROT, BB;PASSOJA, DE;PAULLAY, AJ
当一块金属被拉伸或冲击载荷（拉扯或撞击）断裂时，形成的断裂面是粗糙和不规则的。它的形状受金属的微观结构（如晶粒、夹杂物和沉淀，其特征长度相对于原子尺度较大）以及“宏观结构”影响（如试样的尺寸、形状和断裂开始的缺口）的影响。然而，在各种放大倍数下的反复观察也揭示了介于“微观”和“宏观”之间的各种附加结构，并且尚未以系统的方式得到令人满意的描述。本文所报道的实验表明，存在广泛而明显的中间尺度区，其中的结构可以很好地用分形表面来模拟。引入了一种新的方法——狭缝岛分析法来估计分形维数D。结果表明，该估算值与裂缝剖面分析（一种谱法）所得值一致。最后，硬度是衡量金属韧性的一种指标。
When a piece of metal is fractured either by tensile or impact loading (pulling or hitting), the fracture surface that is formed is rough and irregular. Its shape is affected by the metal's microstructure (such as grains, inclusions and precipitates, whose characteristic length is large relative to the atomic scale), as well as by ‘macrostructural’ influences (such as the size, the shape of the specimen, and the notch from which the fracture begins). However, repeated observation at various magnifications also reveals a variety of additional structures that fall between the ‘micro’ and the ‘macro’ and have not yet been described satisfactorily in a systematic manner. The experiments reported here reveal the existence of broad and clearly distinct zone of intermediate scales in which the structure is modelled very well by a fractal surface. A new method, slit island analysis, is introduced to estimate the basic quantity called the fractal dimension,D. The estimate is shown to agree with the value obtained by fracture profile analysis, a spectral method. Finally,Dis shown to be a measure of toughness in metals.